Most item tracking systems in commercial settings can be classified as either a supply chain system or a manufacturing system. Manufacturing systems generally track items that remain within a facility, whereas supply chain systems generally track items that move into, through and out of a facility. One common supply chain system is a distribution center conveyor system on which boxes or other packages from a receiving area are placed and transported to one or more stations at which the packages are identified, sorted and distributed to appropriate locations depending on the sortation. It is well known in such systems to employ bar code labels to the packages to thereby affix relevant information, for example manufacturer and package contents, that can be read by barcode scanners disposed along the conveyor. The scanner outputs information to a controller that associates the information with the package and outputs the associated information to a host system that can then manage the package's progression to its ultimate destination.
Barcode systems, although having developed to a high degree of reliability, suffer from certain inherent limitations in that they require a line of sight between the barcode scanner and the label, and the barcode label must be applied on the package so as to be optically readable. In contrast, radio frequency identification (RFID) tags do not require an optical line of sight for reading by an RFID reader. However, RFID systems are also prone to various limitations, such as potential damage to system components from electrostatic discharges (ESD). A typical RFID system may include an antenna positioned below a conveyor on which boxes or other packages are placed, the antenna sending and receiving signals in order to retrieve information from the RFID tags on the packages. In turn, received signals are sent to a controller that associates the information within the signals with the relevant packages. During operation of such an RFID system, it is not uncommon for electrostatic charges to build up within the components of the system, primarily the conveyor belt, due to friction between the conveyor belt and the components. When discharged in the vicinity of the antenna, as can occur when the seam of the conveyor's belt approaches the antenna, the ESD can cause a high voltage signal to be detected by the antenna and sent to the reader, possibly causing damage to the reader. Signals with charges of 1000V or more are not uncommon for such ESDs.